The present invention relates to the field of packaging, in particular bags having complementary closure strips.
Numerous packages or bags including such closure strips have already been proposed.
More precisely still, the present invention relates to packages or bags that include a connection zone that is peelabe, i.e. separable, defined between the inside surfaces of the walls of the package or bag.
Numerous packages or bags of this type are also known.
The function of the peelable zone is to improve leakproofing of the package or bag.
Another function is to make it possible to verify whether or not the package or bag has been opened. If the peelable zone of a package or bag has been separated, that informs a potential purchaser that the package or bag has already been opened.
The peelable zone can be provided on the inside or the outside of the closure strips, relative to the inside volume of the package or bag.
Generally, the peelable zone is made by fitting a strip of peelable material on the film constituting the package or bag, i.e. a strip presenting a melting point that is lower than that of the wall of the package or bag.
An embodiment of such a package is to be found in document U.S. Pat. No. 4,925,318.
Nevertheless, it has been observed that the means proposed in the past for making such packages are very complex and do not give full satisfaction. In particular, they do not always make it possible to guarantee that the package is properly leakproof, specifically at the ends of the peelable strip where they join the side edges of the package, because the lengths of the segments of peelable material fed onto the film constituting the package must be shorter than the width of the film.
Attempts have been made to remedy that difficulty by making the peelable zone without adding material, by applying surface treatment to the film.
Nevertheless that has not given full satisfaction either, in particular because it is complex to implement.
An object of the present invention is to improve performance of known packages.
The main object of the present invention is to provide bags or packages presenting leakproofing that is better than that of previously known bags or packages.
In the context of the present invention, the above object is achieved by the method of manufacturing packages, the method comprising the steps which consist in feeding segments of strip or tape of peelable material onto the film that is to form the wall of the package, the length of the segments while they are being deposited on the film being less than the desired package width, in flattening at least the ends of each segment so that, after flattening, the segments cover the width of said package in full, and in fixing each segment of peelable material to the film.
The present invention also provides a machine for implementing the method, and packages obtained thereby.